Physical Causes of Aging in Plastics

Abstract

Abstract A number of physical changes that take place in a polymer below the glass transition temperature without the action of a medium are first described, and are then explained on the basis of changes in supramolecular order. Pure stress crazing with the characteristic self‐limitation of craze growth is then considered. Models are developed to explain stress crazing under the influence of a wetting medium. Attempts to reduce stress crazing are then treated and the article closes with a discussion of the influence of morphological structure on crazing and cracking.